Sensor employing overlapping grid lines and conductive probes for extending a sensing surface from the grid linesCross Reference to Related Applications
This application claims benefit of filing date of U.S. provisional patent application No. 61/942,892 filed on 21/2/2014 and U.S. provisional patent application No. 61/943,733 filed on 24/2/2014 according to the provisions of section 119 of U.S. code 35, the respective disclosures of which are incorporated herein by reference.
FIELD OF THE DISCLOSURE
The present disclosure describes a sensor, such as a fingerprint sensor, for sensing an object located near or around the sensor.
Background
In the electronic sensing market, there are various sensors for sensing objects at a given location. Such sensors are configured to sense electronic characteristics of an object, in order to sense the presence of objects near or around the sensor, as well as other features and characteristics of the sensed objects.
The sensor may be configured to passively detect a characteristic of the object by measuring a parameter such as temperature, weight, or various emissions such as photon, magnetic, or atomic emissions proximate to or in contact with the sensor. An example of this is a non-contact infrared thermometer that detects the blackbody radiation spectrum emitted by the subject from which the temperature of the subject can be calculated.
Other sensors operate by directly stimulating a subject with a stimulus (e.g., a voltage or current) and then using the resulting signal to determine a physical or electrical characteristic of the subject. An example of this is a fluid detector, which consists of two terminals, one to stimulate the medium with a voltage source and the second to measure the current to determine the presence of a conductive fluid (e.g. water).
The impedance data of the two-dimensional array may be created by moving the object over a line sensing array and then performing a line-by-line reconstruction of the two-dimensional image. An example of this is a brushed capacitive fingerprint sensor (swiped capacitive fingerprint sensor) that measures the difference in capacitance between a fingerprint ridge and a fingerprint valley as a finger is dragged across it. Such a sensor reconstructs a two-dimensional fingerprint image, following the fact that individual line information is used.
A simpler way to acquire a two-dimensional image is to create a two-dimensional sensing array. However, such sensors are cost prohibitive due to the large number of sensing points required in the array. An example of this is a two-dimensional capacitive fingerprint sensor. Many such sensors are currently manufactured, but take up to 150mm2Or larger silicon area, and thus toCost is prohibitive for many applications.
These different types of electrical sensors have been used in various applications, such as biometric sensors for measuring properties like fingerprints, medical applications or fluid measurement monitors. Typically, the sensing elements of the various devices are connected to a processor configured to process the object information and to be able to interpret the object features.
There is a need in the art for a device that can provide accurate and reliable sensors for use in different applications, such as fingerprint sensing and/or authentication.
Summary of The Invention
The following presents a simplified summary in order to provide a basic understanding of some aspects described herein. This summary is not an extensive overview of the claimed subject matter. It is intended to neither identify key or critical elements of the claimed subject matter nor delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
Aspects of the disclosure are embodied in one or more conductive probes that extend a sensing surface of an electrical sensor from a surface of a pick-up element of the sensor to a surface of a cover layer disposed over the pick-up element. For example, the sensor may arrange the plurality of pickup elements and the plurality of drive elements in a grid pattern and place the plurality of conductive probes at a plurality of crossing locations so as to create a grid of sensing locations near or on the surface of the cover layer.
Further aspects of the disclosure are embodied in a fingerprint sensor integrated in a device having a cover layer made of an insulating material (e.g., glass, polymethylmethacrylate, or polycarbonate). The fingerprint sensor includes at least one drive line (narrow, elongated drive element) positioned below the cover layer, wherein the drive line is configured to carry a signal that is coupleable to a proximally placed object. The fingerprint sensor further includes at least one pickup line (narrow, elongated pickup element) positioned below the cover layer, wherein the pickup line is oriented substantially perpendicular to the drive line. The pickup lines and drive lines can be separated by a dielectric layer (e.g., a flexible polymer substrate such as kapton). The drive lines and pickup lines may form impedance-sensitive electrode pairs at the locations where the drive lines cross the pickup lines ("crossover locations").
The fingerprint sensor further includes at least one conductive probe, such as a cylindrical conductor, extending substantially through the cover layer. The conductive probe can be positioned proximate the crossover location such that the first end of the conductive probe is proximate the impedance-sensitive electrode pair. For example, the first end of the conductive probe may contact at least a portion of the impedance-sensitive electrode pair. The second end of the conductive probe may define a fingerprint sensing location on or near an exterior surface (e.g., top surface) of the overlay layer.
in an embodiment, the overlay may be part of a screen of the touch-enabled device such that the fingerprint sensor is integrated into the touch-enabled device.
In an embodiment, the conductive probe straddles an edge of the pick-up element. For example, the conductive probe can be placed such that half of the conductive probe directly passes over the pickup element, while the other half of the conductive probe does not directly pass over the pickup element. Other embodiments may involve other ratios (e.g., 5%/95%, 10%/90%, 95%/5%, or any other ratio) between the cross-sectional area of the conductive probe directly across the pickup element to the cross-sectional area of the conductive electrode not directly across the pickup element.
In an embodiment, the sensor includes an m n matrix of drive lines and pickup lines. Each drive line may be connected to the activation circuit permanently or through a switch. Each pickup line may be connected to a buffer or amplifier, either permanently or through a switch. In some examples, m ═ n. The sensor in such an instance may be referred to as a grid sensor. In some examples, m < < n. The sensor in such an example may be referred to as a swipe sensor or a line sensor. The m n pickup lines form an m n impedance sensitive electrode pair. The sensor may be configured to simultaneously activate a plurality of impedance-sensitive electrode pairs to detect a fingerprint feature at a plurality of locations. For example, providing a drive signal to one drive line can couple the drive signal to multiple pickup lines at multiple crossover locations, thereby activating impedance-sensitive electrode pairs at these locations.
In embodiments such as where the sensor is a swipe/line sensor, the activation circuit is adapted to receive input from a touch-enabled display device. The activation circuit may activate one of the sets of drive lines based on input from a touch-enabled display device. The input may include a speed and direction of finger movement across the touch-enabled display device.
In an embodiment, the sensor comprises at least one grounded probe adjacent to the conductive probe. The grounded probe can protect the conductive probe from noise (e.g., crosstalk) and can better focus signals received at the corresponding pickup element. In some cases, a ground plane is placed between the cover layer and the pair of impedance-sensitive electrodes, and a grounded probe is connected to the ground plane.
In embodiments, the conductive probes (e.g., conductive posts) may be formed using fabrication techniques such as milling, laser drilling, etching, Reactive Ion Etching (RIE), mechanical drilling, or any other technique.
the drive element and/or the pick-up element may be located on or below the cover layer. In one example, the drive elements and/or pickup elements may be processed directly on the cover layer by techniques involving metal sputtering, photolithography, and etching. In one example, the drive elements are processed on a separate substrate mounted to the bottom side of the cover layer. In an embodiment, the drive element and/or the pick-up element are integrally formed in the cover layer. For example, wires are etched into the cover layer and filled with a conductive material to form the drive elements and/or the pickup elements.
The sensors may be implemented to have any pattern. In an embodiment, it may be formed in a shape approximating the logo of a device manufacturer (e.g., smartphone manufacturer).
Other features and characteristics of the present disclosure, as well as methods of operation and functions of the related elements of structure and the combination of parts, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures.
Brief Description of Drawings
The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various non-limiting embodiments of the present disclosure. In the drawings, like reference numbers indicate identical or functionally similar elements.
Figure 1 illustrates a top perspective view of an electrical sensor, according to an embodiment of the present disclosure.
Figure 2 illustrates a bottom perspective view of an electrical sensor, according to an embodiment of the present disclosure.
Figure 3 illustrates a perspective view of an electrical sensor, according to an embodiment of the present disclosure.
Figure 4 illustrates a top view of an electrical sensor, in accordance with an embodiment of the present disclosure.
Figures 5-11 illustrate side views of an electrical sensor, according to embodiments of the present disclosure.
FIG. 12 illustrates an embodiment of a drive and sense multiplexing circuit that uses tank circuits to compensate for input loading effects.
FIG. 13 illustrates an embodiment of a drive and sense multiplexing circuit that uses cascaded buffers for each sense to compensate for loading effects.
FIG. 14 illustrates an embodiment of a drive and sense multiplexing circuit that uses a dedicated buffer for each sense to compensate for loading effects.
FIG. 15 illustrates an analog receiver for processing sensed signals and processing circuitry for performing drive line scanning and pickup line scanning.
FIG. 16 illustrates a direct digital conversion receiver for processing sensed signals and processing circuitry for performing drive line scanning and sense line scanning.
Fig. 17 illustrates a schematic diagram of sensing of fingerprint features.
Fig. 18 illustrates the step of collecting a 2D image by means of a sensor system.
Fig. 19 illustrates the steps of authenticating a user by means of a fingerprint sensor.
Fig. 20 illustrates template extraction of a fingerprint image typically used in a user authentication application.
Detailed Description
The present disclosure relates to an electrical sensor for detecting a proximally placed object. In an embodiment, the sensor is a fingerprint sensor that detects surface features (e.g., ridges or valleys) of a finger placed on the electrical sensor. In an embodiment, the electrical sensor operates based on an interaction between a pair of electrodes comprising a drive element and a pickup element. The pick-up element may be capacitively coupled to the drive element and may sense a signal passing from the drive element to the pick-up element. The characteristics of the proximally placed object may be detected based on whether the sensor detects a change in the signal received at the pickup element. In embodiments where the electrical sensor is a fingerprint sensor, the sensor may detect whether a particular location on the sensor surface is directly under a ridge or a valley of the fingerprint. The ridges of the fingerprint may provide a low impedance path to ground potential, while the valleys of the fingerprint may provide a high impedance, similar to the case where there is no object placed in close proximity at all. Thus, if the fingerprint ridge contacts the pickup, it may significantly attenuate the signal detected at the pickup. Conversely, if the pickup is directly below the valleys of the fingerprint, the signal detected at the pickup may be substantially unattenuated. Thus, the electrical sensor in this embodiment can distinguish between fingerprint ridges and fingerprint valleys based on the signal detected at the pickup element.
In an embodiment, the electrical sensors form a grid to detect surface features of the proximally placed object at a plurality of locations. The grid comprises a plurality of parallel drive lines, each connectable to a drive source, and the grid comprises a plurality of parallel pickup lines oriented transverse (preferably perpendicular) to the drive lines. The drive lines are separated from the pickup lines by an insulating (e.g., dielectric) layer. Thus, each drive line can be capacitively coupled to a pickup line. In this embodiment, the drive lines may form one axis of the grid (e.g., the X-axis) while the pickup lines form another axis of the grid (e.g., the Y-axis). Each location where a drive line and a pickup line intersect may form an impedance-sensitive electrode pair. The impedance-sensitive electrode pair can be viewed as a pixel (e.g., X-Y coordinates) at which surface features of a proximally-placed object are detected. The grid forms a plurality of pixels that together can create a layout of surface features of adjacently placed objects. For example, the pixels of the grid may be mapped with locations of ridges of a fingertip touching the electrical sensor and locations of valleys of the fingertip. The layout can be used as a pattern to match the ridge/valley patterns stored in the database. Additional details of fingerprint sensors having overlapping drive and pickup lines are discussed in more detail in U.S. patent No. 8,421,890 entitled "Electronic image manager using an image sensor grid array and method of mapping" and in U.S. patent application publication No. US 2012-0134549 entitled "Biometric sensing," the disclosures of each of which are incorporated herein by reference in their entirety.
The present application not only contemplates the use of overlapping drive and pickup lines to form a sensing grid, but also contemplates that repeated contact between an adjacently placed object and a pickup element may eventually damage the pickup element. Other environmental factors, including humidity, corrosion, chemical or other mechanical wear, can also damage the pickup. Furthermore, radiation, noise and other environmental factors at the pickup element may interfere with the accuracy of the electrical sensor. Although an insulating film may be placed over the pickup, the film needs to be sufficiently thin so that it does not interfere with the detection of surface features of an adjacently placed object. However, the thin insulating film may wear itself due to environmental factors and does not protect the electrical sensor from reliability issues.
In an embodiment, the disclosed aspects address the above-described problems by providing one or more conductive probes (e.g., cylindrical conductors) that allow the distance between the pickup element and the sensing surface of the sensor (e.g., the outer surface of the sensor) to extend. In one orientation, each conductive probe is a vertical column that extends over a horizontally oriented sensor grid. The vertical pillars may extend from the pickup elements of the impedance-sensitive electrode pairs to the sensing surface. More generally, each conductive probe can extend from a pixel location where a drive line crosses a pickup line toward the sensing surface. One or more conductive probes may be embedded in a cover layer made of an insulating material, which is arranged on top of the pick-up element.
In this embodiment, as the one or more conductive probes extend towards the sensing surface of the electrical sensor away from the sensor grid, they enhance the ability of the pick-up element to detect features of an object at the sensing surface. Thus, the enhanced detectability allows the insulating cover layer to have a greater thickness than the insulating film described above. A thicker insulating cover layer may provide better protection against environmental conditions. In examples where the electrical sensor is used in a touch screen device, the insulating cover layer may be a transparent material of a portion of the touch screen. Such a configuration provides a way to integrate electrical sensors into a touch-enabled device.
figure 1 illustrates portions of an example electrical sensor 100 for sensing surface features of an object placed in proximity to a sensing surface 101 of the sensor 100. The sensor 100 includes a plurality of drive elements 102 and a plurality of pickup elements 104. In one embodiment, the drive elements may be formed as substantially parallel elongated, plate-like strips of electrically conductive material (e.g., copper, aluminum, gold), which may be referred to as drive wires or plates. The pick-up elements may be formed as elongated, plate-like strips of substantially parallel conductive material, which may be referred to as pick-up lines or plates. The insulating layer 106 separates the drive lines and the pickup lines. The drive element 102 and the pickup element 104 are oriented transverse to each other, and in one embodiment perpendicular to each other.
Electrical sensor 100 also includes a plurality of conductive probes 108 (e.g., elongated conductive elements), which conductive probes 108 extend from pickup lines 104 toward sensing surface 101. As shown in fig. 1, a first end (e.g., a lower end in the figure) of the conductive probe 108 is adjacent to a location where the drive line 102 crosses the pickup line 104 (a crossing location). In an embodiment, the first end is in contact with a portion of the pair of impedance-sensitive electrodes formed at the crossover location. In an embodiment, the first end is proximate to, but not touching, the pair of impedance-sensitive electrodes. In this embodiment, the conductive probe is capacitively coupled to the impedance-sensitive electrode pair. In an embodiment, the conductive probe extends substantially through the covering layer 110 made of an insulating material. As explained subsequently in this disclosure, the second end (e.g., upper end in the figures) of the conductive probe 108 may terminate at (e.g., flush with), above, or below the top surface of the overlay layer. As illustrated in fig. 1, the top surface of the cover layer 110 may be the sensing surface 101, or may be separated from the sensing surface by one or more other layers.
In an embodiment, the insulating material used for the cover layer 110 is transparent. In an embodiment, the insulating material 110 is selected from the group consisting of glass, polymethylmethacrylate, and polycarbonate. If the insulating material 110 includes glass or a glass substitute (e.g., acrylic glass (polymethylmethacrylate) or polycarbonate), the conductive probe 108 may be formed as a via in the insulating material. In some cases, the cover layer 110 may be made of a thick flexible polymer substrate instead of glass. The conductive probe can be embedded within a polymer substrate. For example, etching techniques may form pillars in the capping layer 110, which may be filled with a conductive material (e.g., copper, indium tin oxide, conductive paste (e.g., made of carbon nanotubes, graphite powder, copper), conductive adhesive (e.g., silver, copper, graphite), or conductive polymer) by deposition, sputtering, electroplating, or other techniques. In another example, the conductive probe may be first formed into a narrow, elongated element, and then the insulating material for the cover layer 110 may be deposited to embed the conductive probe.
In an embodiment, the conductive probe may be made of a transparent material, such as an Indium Tin Oxide (ITO) material, which may be imperceptible to a user. In an embodiment, the conductive probe may have a cross-section that is small enough to be imperceptible to a user.
The embodiment in fig. 1 includes a plurality of drive lines 102 and a plurality of pickup lines 104. As discussed above, the drive lines may form one axis (e.g., the X-axis) of the grid (array) while the pickup lines form another axis (e.g., the Y-axis). Each location where a pickup line crosses a drive line (i.e., a crossing location) may form an electrode pair that is impedance sensitive for use as a pixel in the grid. As also discussed above, the conductive probe 108 may extend from the intersection location toward the sensing surface 101. Thus, in FIG. 1, the conductive probe 108 effectively extends the sensing surface in a vertical direction from the plane defined by the tops of the pickup lines 104 to the top surface 101. For example, the conductive probes 108 extend from at or near the pickup lines 104 to a plurality of locations 112 at or near the sensing surface 101. The conductive probes 108 have their respective impedance-sensitive electrode pairs better detect changes in surface impedance at or near the location 112, and thus better detect surface features of objects at or near the location 112. For a touch screen device, the use of a conductive probe integrates the drive and pickup elements of the sensor 100 within its touch screen. Such integration saves space on the touch screen device by having the sensor 100 share its sensing surface with the touch surface of the touch screen device. The use of the conductive probe 108 also increases the range of allowable thicknesses of the cover layer 110.
In an embodiment, the lower end of each conductive probe 108 straddles the edge of the pickup line 104, and thus, the lower end of the probe partially overlaps the insulating layer adjacent the pickup line 104. In the embodiment illustrated in fig. 1, half of the width of the conductive probe 108 is directly over the corresponding pickup line 104, while the other half of the width of the conductive probe 108 is over the adjacent insulating material. In other embodiments, the conductive probe 108 may have 5% of its width directly above the pickup line 104 and 95% of its width above the adjacent dielectric material, or may have any other ratio so placed (e.g., 10/90, 90/10, 95/5).
As shown in fig. 1 and 4, in an embodiment, the activation circuit 126 provides a signal to the drive line 102. In addition, a detection circuit 120 (e.g., an amplifier or buffer) detects the signal received at the pickup line 104. In the embodiment illustrated in FIG. 1, activation circuitry 126 is provided to each drive line and detection circuitry 120 is provided to each pickup line. In other embodiments, sensor 100 may include fewer activation circuits and/or fewer detection circuits 120. For example, multiple drive lines may share the activation circuit 126 via a multiplexer, while multiple pickup lines may share the detection circuit 120 via a multiplexer. In the embodiment of fig. 1, the sensor 100 includes a switch 124 that can disconnect the drive line 102 from the activation circuit 126, and includes a switch 122 that can disconnect the pickup line 104 from the detection circuit 120. The switches allow the sensor 100 to activate only one drive line for a period of time and detect signals at various crossover locations along the activated drive line. In some cases, sensor 100 may detect signals from multiple pickup lines simultaneously. In some cases, the sensor 100 may detect a signal from one pickup line while connecting one or more adjacent pickup lines to ground. The grounded pickup line protects the measured pickup line from noise. The detected signals may indicate surface features at the X-Y coordinates corresponding to activated drive lines and measured pickup lines. Sensor 100 may sequentially activate other drive lines to detect surface features at other X-Y coordinates.
the activation circuit 126 and the detection circuit 120 may be located anywhere. In some instances, they may be part of sensor 100. For example, they can be embedded within the cover layer 100, where they can be adjacent to or below the drive and pickup lines. In some examples, they may be provided as separate components (e.g., an activation component and a detection component) that are manufactured or sold separately from the sensor 100.
In embodiments, the drive lines and pickup lines can be formed by means of lithographic techniques (e.g., deposition or ion exchange metallization, mask formation, etching). For example, the drive plate and/or the pickup plate may be formed by depositing a conductive layer, patterning a mask over the conductive layer, and etching the conductive layer into a plurality of parallel lines. The various layers may be formed one on top of the other using such techniques. As illustrated in fig. 1 and 2, forming the respective layers in this manner may result in a stepped shape of the insulating layer 106 and the driving board 102.
More specifically, in one embodiment, the pickup elements 104 are arranged in a substantially parallel configuration, for example, on a surface of the cover layer 110. As shown in fig. 2, a dielectric layer 106 is then deposited over the pickup element 104 in such a way that: a dielectric layer covers each pickup element and extends into the gaps between adjacent pickup elements, defining spaced apart slots parallel to the pickup lines 104 in the lower surface of the dielectric layer 106. The drive elements 102 are then deposited in parallel strips over the dielectric layer 106 in a manner that causes portions of each drive line 102 to flow into and fill the slots formed in the dielectric layer 106.
Fig. 3 illustrates an alternative sensor 100A in which the drive lines 102A, the pickup lines 104A, and the insulating layer 106A are planar. In general, the drive lines, insulating layer, pickup lines, and capping layer can have any shape.
In embodiments, the sensor includes other layers. For example, the conductive layer can be formed under the drive and pickup lines. The conductive layer protects the pickup lines from noise and provides a ground potential. In an embodiment, an additional probe may be formed and electrically connected to ground potential. A grounded probe may be placed adjacent to one or more conductive probes 108 and may protect the one or more conductive probes 108 from noise.
in embodiments, the structures (e.g., vias) of the conductive probe may be formed by mechanical drilling, chemical etching, reactive ion etching, laser drilling, and/or other micromachining processes.
Figure 4 illustrates a top view of electrical sensor 100. The figure illustrates each conductive probe 108 riding across the boundary between a pickup line 104 and an adjacent insulating layer 106. The figure also shows that a plurality of conductive probes 108 can be arranged in a grid pattern to substantially correspond to the intersection locations between the drive lines 102 and the pickup lines 104.
Figure 5 illustrates a side view of electrical sensor 100. The illustrated embodiment shows each conductive probe 108 forming a via through the cover layer 110. Although the illustrated embodiment shows the conductive probe 108 in contact with the pick-up plate 104, in other embodiments, the conductive probe 108 may be electrically insulated from the pick-up plate 104. Further, while the illustrated embodiment shows the tip of the conductive probe 108 flush with the sensing surface 101, in other embodiments, the tip may be located below the sensing surface such that the cover layer 110 better protects the conductive probe 108 against environmental conditions.
Fig. 6 illustrates a situation where the top surface of the cover layer 110 contacts the sensing surface 101 of an adjacently placed object, such as a fingertip 200. The coupling between the drive lines 102 and the pickup lines 104 in fig. 6 can be modeled as a capacitance. The capacitance includes fringe capacitance from a fringe electric field between two lines, which is explained later in this disclosure. The coupling between the drive line 102 and the conductive probe 108 can also be modeled as a capacitance.
fringe electric fields are illustrated in fig. 7, fig. 7 showing field lines 302 between the drive line 102 and the conductive probe 108, and field lines 304 between the drive line 102 and the pickup lines 104, in the event that no object is proximate to the electrical sensor 100. Fig. 7 illustrates the advantage of placing the conductive probe 108 straddling the boundary between the pickup line 104 and its adjacent dielectric layer 106. More specifically, in some examples, the detection performed at the pickup lines 104 relies on detecting a signal provided by the fringe electric field coupling the pickup lines 104 and the drive lines 102. A change in the fringe electric field may indicate an object in proximity to electrical sensor 100. However, as illustrated in fig. 7, the probe 108 is a conductor that prevents the presence of an electric field within the conductor. In some examples, each of the conductive probes 108 can be placed in any one of a number of positions relative to the drive plate and the pickup plate, such as a position on top of the drive plate 102 and centered over an insulating material adjacent to the pickup plate 104, a position centered over the pickup plate 104, a position straddling the pickup plate 104 and the drive plate 102, or any position therebetween. In FIG. 4, three of these positions are illustrated as positions 108-1, 108-2, and 108-3, respectively. Fig. 7 illustrates a straddle configuration in which the conductive probe 108 is moved toward one edge (e.g., the left edge) of the pickup element 104. Such a configuration optimizes the fringe electric field to form pickup lines 104 near the other edge (e.g., the right side edge).
Fig. 8 illustrates a case where an object such as a fingertip 200 touches the sensing surface 101 of the sensor 100. The figure shows that the ridges 202, 204 of the fingertip 200 provide a low impedance path to ground. More specifically, the ridges 202, 204 of the fingertip 200 may be in physical contact with the conductive probes 108A and 108C such that the ridges 202, 204 provide an AC path to ground. For example, grounding the conductive probe 108A may ground the pickup line 104A, thereby attenuating the signal received at the pickup line 104A. In other words, the fringe electric field 304A between the drive line 102 and the pickup line 104A, and the fringe electric field 302A between the drive line 102 and the conductive probe 108A, can be altered when the respective conductive probe 108A contacts the ridge 202. The modification may attenuate the strength of the fringe electric field at the pickup lines 104A, which may attenuate the signal detected at the pickup lines 104A. Thus, for fingerprint sensing, the signal attenuated at the intersection between the pickup lines 104A and the drive lines 102 may be interpreted as a fingerprint ridge at the intersection or the location of the probe.
FIG. 8 also shows that when the valleys 206 of the fingerprint 200 are above the conductive probe 108B, the fringe electric fields 304B between the drive lines 102 and the pickup lines 104B and the fringe electric fields 302B between the drive lines 102 and the conductive probe 108B are substantially unaffected under the impedance-sensitive electrode pairs. More specifically, the figure illustrates a valley 206 located above the conductive probe 108B. The valleys 206 provide a gap that electrically reduces the impedance of the conductive probe 108B to the fingertip 200 compared to the fingertip 200 in contact with the conductive probe 108A at the ridge 202, thereby reducing the amount of signal attenuation at the pickup line 104B compared to at the pickup line 104A.
Fig. 9 illustrates an embodiment where the dielectric region 130 separates the conductive probe 108 and the pickup line 104 on the top, bottom, or both ends of the sensor body 101. The gap can be modeled as a capacitance coupling the conductive probe 108 to the pickup line 104. The capacitive coupling may provide an AC ground for the pickup lines 104 when the ridges of the fingertip 200 are in contact with the corresponding conductive probe 108 of the pickup line 104.
Similar to fig. 8, fig. 9 also shows that grounding the conductive probe 108 can alter the fringe electric field around the pickup line 104. The changing fringe electric field may result in an attenuated signal being detected at the intersection between the drive lines 102 and the pickup lines 104. Attenuation may be interpreted as the object coming into contact with the intersection location or the location of the probe.
FIG. 10 illustrates an embodiment in which an insulating layer 112 is located on the top surface of the cover layer 110 over the conductive probes 108. In some examples, insulating layer 112 includes a material different from the insulating material of capping layer 110. In some examples, insulating layer 112 may comprise the same material that comprises capping layer 110. In such instances, the insulating layer 112 may be considered a different layer than the capping layer 110, in that the insulating layer 112 may be deposited or otherwise formed after the capping layer 110 is formed. In some cases, insulating layer 112 may be transparent.
in FIG. 10, the sensing surface 101 is located at the top surface of the insulating layer 112, rather than the top surface of the capping layer 110. The insulating layer 112 can provide capacitive coupling between the conductive probe 108 and an object (e.g., a ridge of a fingertip) touching the sensing surface 101. The dielectric constant epsilon and thickness d of the insulating layer 112 can be selected to provide a low impedance path from the conductive probe 108 to AC ground when an object, such as a ridge of a fingertip, touches the sensing surface 101.
FIG. 11 illustrates an embodiment that also includes an insulating layer 112A placed over the conductive probe 108. The illustrated embodiment illustrates an electrode 105 disposed on the top surface of the capping layer 110. In some cases, such electrodes may extend the surface area of the conductive probe at the top surface of the cover layer 110. The increased surface area may increase the capacitive coupling between an object touching the sensing surface 101 and the conductive probe 108. In some examples, the electrode 105 is electrically connected to the conductive probe 108. In some examples, electrode 105 is electrically insulated from conductive probe 108, but insulation between electrode 105 and conductive probe 108 can still provide capacitive coupling therebetween.
In an embodiment, the sensor comprises at least one grounded probe adjacent to the conductive probe. The grounded probe can protect the conductive probe from noise (e.g., crosstalk) and can better focus signals received at the corresponding pickup element. In some cases, a ground plane is placed between the cover layer and the pair of impedance-sensitive electrodes, and a grounded probe is connected to the ground plane. For example, referring back to fig. 1, the sensor 100 may include a second plurality of conductive probes. The probes in the second plurality of second probes may have the same dimensions as the conductive probes 108, or may have different dimensions (e.g., may be thicker or thinner, and may be shorter or longer). Each of the second plurality of second probes may be placed between the conductive probes 108. In one example, each of the second plurality of probes can be disposed along an imaginary line connecting the two conductive probes 108. In one example, the second plurality of probes may be arranged such that the conductive probes 108 and the second plurality of probes form a staggered pattern (e.g., one of the second plurality of probes is disposed between four adjacent conductive probes 108). The sensor 100 may have another conductive layer that serves as a ground layer. For example, a ground layer may be formed under the driving line 102. The ground layer and the drive line 102 may be separated by another insulating (e.g., dielectric) layer. Each of the second plurality of conductive probes may extend through the insulating layer 106 and the other insulating layers to electrically connect to the ground plane. Each of the second plurality of conductive probes may extend to be flush with the sensing surface 101, or may terminate at a location below the sensing surface 101. As discussed above, the plurality of second conductive probes may help focus the signal at the pickup element 104.
The structure described according to the above embodiments provides advantages such as:
Design of
Ergonomics and usability
Simplified integration and enhanced persistence
User feedback on increased biometric performance
Direct interaction with application graphics and animations
Additional details for forming a probe card having conductive probes, a drive plate, and a pickup plate (including other embodiments and other arrangements for such structures) are provided in norwegian patent application 20131423, norwegian patent application 20130289, and U.S. patent application No. 14/183,893 (U.S. patent application publication No. 2014/0241595), which are incorporated herein by reference in their entirety.
The following figures illustrate example circuits configured to provide drive signals to drive lines and process signals detected at pickup lines.
Fig. 12 shows a circuit diagram of an example of a topology drop point sensor front end that uses a single pole double throw switch bank or SPDT bank to scan the pick plate rows and single pole single throw switch banks to multiplex the pick plate columns. The sensor of FIG. 12 includes top plates (i.e., pickup plates) 902a, 902b, … 902n, bottom plates (i.e., drive plates) 906a-906n, and a reference top plate (i.e., pickup plate) 905. The carrier signal source 916 generates drive signals for the backplanes 906a-906n, which backplanes 906a-906n are selectively connected to the carrier signal source 916 via switches controlled by drive control lines 940.
In FIG. 12, we see a snapshot of the analog switches 944a-944n (controlled by switch control line 946) at the beginning of the scanning process. Only backplane 90a (active backplane) is connected to carrier signal source 916. Only the first SPDT switch 944a is shown in the "closed" position, which causes the pickup plate 902a to conduct its plate signal into the differential amplifier 980. The remaining pickup plate is shorted to ground via switch 944n, preventing any pickup signals received by the remaining pickup plate from entering differential amplifier 980.
Each SPDT has a parasitic capacitance 945 due to the fact that real world switches do not give perfect isolation. In fact, the amount of isolation decreases with frequency, typically modeled by a parallel capacitor across the switch poles. By using SPDT switches we can connect this capacitance in parallel to ground when the individual plates are passive. Since there are large arrays of switches equivalent to the number of plates picked, typically 200 for a 500dpi sensor, the effective capacitance in parallel to ground is a multiple of that number. Thus, if a given switch has a parasitic capacitance of 0.5 picofarads and there are 200 pickups, then the total parallel capacitance will amount to 100 picofarads.
To prevent such large capacitances from transferring the majority of the received signal from the active pick-up to ground, it is advisable to use a compensation circuit in this example. This is accomplished by using a resonant inductor 939, forming a typical band pass filter circuit connected to a parasitic capacitor 945 (one for each switch), along with tuning capacitors 934 and 937. The two-step zero & peak tuning calibration procedure is used when tuning capacitors 934 and 937 are each tuned with inductance 939 using the same drive signal on both the positive and negative inputs of differential amplifier 980. The two band pass filters formed by the inductor 939 and the resonant capacitors 934 and 937, respectively, will be tuned to the same center frequency when the differential amplifier 980 has no zero signal. Capacitors 934 and 937 and inductor 939 are then tuned together using differential input signals on the positive and negative inputs of differential amplifier 980 having opposite 180 degree phases. They are incremented in the lock step until the exact drive carrier frequency is reached, which occurs when the output of the differential amplifier 980 is at its peak, making the center frequency equal to the exact frequency of the carrier drive signal 916.
In a system implementation, a calibration procedure will be performed before each fingerprint scan to minimize the drift of the filter over time and temperature. The resonant inductor 939 needs to have a Q or quality factor of at least 10 to give the appropriate bandwidth characteristics of the filter necessary to optimize the signal-to-noise ratio.
Fig. 13 shows an alternative example of a device (front-end circuit 900b) employing multiple sets of boards 907a, 907b commonly grounded, each with its own differential amplifier 980a, 980 b. The #1 group 907a of the pickup lines are selectively controlled to the differential amplifier 980a by switches 944a-944n connected by a pickup control line 945, and the #2 group 907b of the pickup lines are selectively connected to the differential amplifier 908b by switches 945a-945n controlled by the pickup control line 945.
Dividing a large number of parallel pick-up plates into groups each containing a smaller number of plates is an alternative architecture that would not require the use of tuned band pass filters at the front end, as the parasitic switching capacitance would be greatly reduced. This would have two possible advantages, firstly lower cost and secondly the ability to have a frequency agile front end. In this figure we have the first switch 944a of group 907a as a snapshot of the active front-end. All other switch groups 907b are shown inactive, shorting their respective boards to ground. Thus, only the voltage or current differential amplifier 980a has any board signals conducted to it, and the voltage or current differential amplifier 980b shorts both its positive and negative inputs to ground through its respective switches 945a-945n and 945r, preventing any signals from these sets from contributing to the overall output.
Each of the differential amplifiers 980a, 980b is added to the summing amplifier 985 through a resistor 987a, 987b, respectively. In this snapshot, only differential amplifier 980a has a plate signal passed into it, so it independently generates a signal to the input of summing amplifier 985. This process is repeated sequentially until all or substantially all of the switch sets 907a, 907b, etc. and the switch plates 944a-944n, 945a-945n, etc. of the entire array are completely scanned.
By splitting the pick-up array, the capacitive input load on each plate is reduced from the number of switches of the full array to the number of switches within a given plate group. For example, the 196 potential pickup pads are divided into 14 groups of 14 pads, with the capacitive load equal to the parasitic capacitance of the 14 switches (944), plus the capacitive load of the differential amplifier. If the analog switch 944 is constructed with very low parasitic capacitance, the overall input load will be small enough that no bandpass circuits in the front end are needed to resonate out the load capacitance. As integrated circuit fabrication technology improves, we will be able to design smaller switches with smaller parasitic capacitances, making this approach more attractive.
Fig. 14 illustrates another example of a front-end circuit using a separate board buffer multiplexed into a second stage differential amplifier.
The buffers 982a to 982n as shown are special buffers designed to have very low input capacitance. In one embodiment, these buffers can be configured as a single stage cascaded amplifier in order to minimize drain-gate miller capacitance and die area. To better maximize the board-to-board isolation, two sets of switches can be used for each input. Analog switches 930a-930n are included in this example to multiplex each selected buffer into differential amplifier 980. Buffer power switches 932a-932n are included to simultaneously power down all other input buffers that are not selected. This effectively puts them at ground potential. An alternative embodiment is to place an input analog switch in front of each amplifier to allow shorting of the unused plates directly to ground. One effect of this approach may be an increase in the input load capacitance of each plate.
Fig. 14 shows a snapshot of the scanning process, where the bottom plate 906a is active and the top plate 902a is sensed through a buffer 982a having power supplied to it through a switch 932 a. Analog switch 930a is closed, passing it to differential amplifier 980. All other buffer outputs are disconnected from the differential amplifier 980 via analog switches 930b-n and power switches 982 b-n.
The positive input of differential amplifier 980 is always connected to reference plate 902r through a low input capacitance buffer 982r, providing a "null" signal reference to the amplifier. The differential amplifier 980 is used to subtract out noise and common mode carrier signals in addition to providing a "null" reference carrier value.
Fig. 15 illustrates a particular embodiment of a landing point sensor 1000 implemented in conventional analog receiver technology. The analog front end begins with a differential amplifier 1080 where the selected pickup pads 1002a-n are subtracted from a reference pad 1005, the reference pad 1005 being located outside the finger contact area, providing a reference signal equivalent to an ideal fingertip valley. A programmable gain stage or PGA1090 follows the differential amplifier 1080, but can be integrated into the same block that provides both gain and reduction in a single stage. PGA1090 is designed with a gain range width sufficient to compensate for product variations in board etching and solder mask thickness between layers.
Control processor 1030 orchestrates scanning of the two-dimensional sensor plate array. The drive plates/columns 1006a-1006n are sequentially activated by backplane scan logic 1040 in control processor 1030 via drive control lines 1042. When the selected drive plate is activated, it is connected to a carrier signal source 1016. All inactive drive boards are connected to ground. The active drive plates remain open long enough to pick up the entire row of boards 1002a-n before activating the next drive plate in the sequence, scanned by top plate scan logic 1045 in control processor 1030, which control processor 1030 sequentially closes and then opens analog switches 1030a, 1030b, … 1030 n.
Analog mixer 1074 multiplies the gain-raised plate signal by reference carrier 1013. The result is a typical spectrum of harmonic products at multiples of the baseband loading wave frequency. Analog low pass filter 1025 is used to filter out unwanted harmonics and must have a sharp enough roll to attenuate the information associated with the second harmonic without losing baseband information.
Following the low pass filter 1025 is an amplifier 1077 followed by an a/D converter 1074, the a/D converter 1074 must sample at a rate at least twice the pixel rate to meet the nyquist criterion. Memory buffer 1032 within control processor 1030 stores the a/D samples locally at a sufficient scale to accommodate the worst-case latency of the host controller. a/D sample control lines 1078 provide the converter with a sampling clock to obtain sequential pixel information created by the ordering of the plate rows and plate columns.
FIG. 16 shows an example of one embodiment of a landing sensor 1100 implemented in direct digital conversion receiver technology. In this example, the analog front end begins with a differential amplifier 1180 in which the selected pickup plate 1102a-n is subtracted from a reference plate 1105, the reference plate 1105 being located outside the finger contact area, providing a reference signal equal to the ideal finger valley. The electrical subtraction of these signals performs several functions: first, the broadband common mode is subtracted; second, subtracting the reference plate 1105 provides a relative reference signal equivalent to an ideal valley; third, common mode carrier signals in both plates that are coupled other than through the finger are also subtracted. Common mode cancellation is particularly important in high RF noise environments. First order carrier cancellation of etch variations in the pickup plate also occurs when we subtract the carrier that is coupled in by other methods than by a finger placed on the sensor. This is critical for low cost mass production.
a programmable gain stage or PGA 1190 follows differential amplifier 1180, which differential amplifier 1180 can be readily combined into a single differential amplifier that includes programmable gain typically done in modern integrated circuit designs. PGA 1190 is designed with a gain range width sufficient to compensate for product variations in the plate etch and solder mask thickness between layers.
Control processor 1130 orchestrates the scanning of the two-dimensional sensor plate array. The drive plates/columns 1006a-1006n are activated sequentially via drive control lines 1142 by backplane scan logic 1140 in control processor 1130. When the selected drive plate is activated, it is connected to a carrier signal source 1116. All inactive drive boards are connected to ground. Prior to activating the next drive plate in the sequence, the active drive plate remains on long enough for the entire row of pickup plates 1102a-n to be scanned by ceiling scan logic 1145 and captured by A/D converter 1125, which ceiling scan logic 1145 sequentially connects pickup plates 1102a-n to differential amplifier 1180 via analog switches 1130a, 1130b, etc.
The a/D converter 1125 is sampled at a rate at least twice the carrier frequency to meet the nyquist criterion. The a/D sampling control line 1107 provides the converter with a sampling clock to obtain the sequential pixel information created by the ordering of the plate rows and plate columns.
Following the a/D converter is a digital mixer 1118 that digitally multiplies the a/D output at the carrier frequency by a reference carrier generated by a digitally controlled oscillator 1110 (coupled to control processor 1130 via oscillator frequency set line 1146). The result is that the signal is down-converted to baseband with the carrier removed. There are other unwanted spectral components resulting from this process, i.e., the dual time carrier sidebands, which can be easily filtered out.
A decimator and digital filter combination 1120 follows the digital mixer 1118. The block performs a sampling down-conversion, reducing the sampling rate from at least twice the carrier frequency to at least twice the much lower pixel rate. The digital filter will typically include a cascaded integrator-comb filter or CIC filter that removes the mixing unwanted spectral byproducts and improves the signal-to-noise ratio of the receiver. CIC filters provide an efficient way to create narrow band pass filters after mixing the signal down to baseband with a digital mixer. The CIC filter may be followed by a FIR filter that operates at a lower decimation rate to correct for band pass roll-off.
With a reduced sampling rate on the order of about 100:1, a relatively small control processor buffer (1132) can be used to capture the entire fingerprint. For example, a 200 × 200 array generating 40k pixels can be stored in a 40kb buffer. This is in contrast to swipe sensors which must scan part of the image frame at a fast enough rate to keep up with the fastest allowable swipe speed, which is typically around 200 ms. At the same time, a two second slow swipe must also be incorporated, requiring ten times the storage as the fastest one. Various techniques have been developed to discard redundant sample lines prior to storage, but even so, the need for real-time storage of the swipe sensor is much greater. This is a key factor in on-chip matching applications where storage capacity is limited. In addition, the drop point sensor does not exceed the user's patience in keeping their finger in position with real-time data acquisition or processing requirements of the host processor.
Fig. 17 illustrates how a device configured according to the present disclosure may be applied to a fingerprint sensing application. The user places a finger bearing a fingerprint (1510) over a grid of sensors formed by the intersection of drive plates (1506a-1506n) and pickup plates (1502a-1502 m). Image pixel 1561a senses the area of the fingerprint over the electrode pair of drive plate 1506a and pickup plate 1502a, pixel 1561n senses the intersection of drive 1506n and pickup 1502a, and pixel 1562n senses the area over the intersection of drive 1506n and pickup 1502 m.
Figure 18 illustrates the steps required to collect a fingerprint image as shown in figure 17 using the embodiment shown in figures 12-16. Image capture begins at step 1601. As part of the initialization, a row counter is initialized to 1 in step 1602. Step 1603 is the start of the line scan sequence. At the beginning of each row, a column counter is set to 1 in step 1603. In step 1604, the top plate scan logic 1145 activates the corresponding analog switch (one of 1130a through 1130 n) for the selected row. In step 1605, sensing of a single pixel begins when the appropriate drive plate (one of 1106a to 1106 n) is activated by backplane scan logic 1140 with carrier signal 1116. In step 1606, the signal from differential amplifier 1180 is resampled by a/D converter 1125 after being processed by programmable gain amplifier 1190. The digital mixer 1118 down-converts the sample mixing to the baseband frequency set by the digital oscillator 1110. The baseband signal is then filtered by a digital decimation filter 1120 to generate a signal level value for the current pixel. The functions performed for this step in the embodiment of fig. 16 can alternatively be performed by a corresponding analog receiver shown in fig. 15 or other functionally similar arrangement. In step 1607, the signal level values obtained in step 1606 are stored in appropriate locations in memory buffer 1132, corresponding to the currently selected row and column. The number of columns is incremented in step 1608 and tested in step 1609 to determine if the current row collection has been completed. If the row has not completed, we return to step 1605 to collect the next pixel in the row. If the row has been completed, we proceed to step 1610 and increment the row number. In step 1611, we test the number of rows to determine if all rows have been scanned. If not, flow returns to step 1603 to return to the first column to start the next row. Once all rows have been scanned, image capture is complete and we proceed to step 1612, at which point the image is ready for further processing or transfer to long term memory.
Those skilled in the art will recognize that the row and column scan order may not directly correspond to the physical location in the array, as some embodiments may more optimally sample in an interleaved manner.
In fig. 19 and 20, examples for a user authentication application are shown. In step 1701, a system level application on the processor requires user authentication. In step 1702, the user is prompted to provide a finger for authentication. The system waits for the presence of a finger to be detected in step 1703. This may be performed by collecting reduced size images as described in fig. 18 and 20 and testing the finger images, or via other dedicated hardware. Once the presence of a finger is detected, a complete image is collected in step 1704 using the method described in FIG. 18 or other substantially similar method. The image is then stored and converted to a template in step 1705, typically consisting of a map of the location and type of detail points (e.g., bifurcation 1710 and end 1711), or possibly a map of the frequency and orientation of ridges, or some combination of both. The template is then compared in step 1707 with one or more registered templates retrieved from the persistent template store in step 1706. If a match is found, the user is authenticated and access to the application is granted in step 1708. If no match is found, the user is denied and access is denied in step 1709.
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad disclosure, and that the invention disclosed herein is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and various alternative arrangements and/or numbers of connections, arrangements and numbers of transistors forming a circuit, and other features and functions may be made without departing from the spirit and scope of the present disclosure. Similarly, components not explicitly mentioned in the specification may be included in various embodiments of the disclosure without departing from the spirit and scope of the disclosure. Also, as will be clear to one of skill in the art, the different process steps and integrated circuit fabrication services described as being performed to fabricate certain components in the various embodiments of the present disclosure can be readily performed in different configurations of components that are fabricated in whole or in part or not explicitly mentioned in the specification, without departing from the spirit and scope of the present disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.
Moreover, the present invention has applications in many fields, particularly in biometric sensors. For example, fingerprint sensors and other biometric sensors are increasingly being accepted for use in a wide variety of applications for security and convenience reasons. Devices, systems and methods configured in accordance with the present invention have improved security of the biometric authentication process without increasing the cost of the system. Furthermore, the present invention extends to devices, systems, and methods that would benefit from verification of components. As discussed above, the present invention includes the ability to have a host and sensors with any combination or subset of the above components arranged and configured in a manner best suited for the intended application of the system. It will be appreciated by those skilled in the art that various combinations and permutations of the components described herein are possible within the spirit and scope of the invention, as defined by the appended claims, their equivalents, and expressed claims and their equivalents in future related applications.
The invention may also relate to functions performed by a computer processor, such as a microprocessor. A microprocessor may be a specialized or special purpose microprocessor configured to perform specific tasks in accordance with the present invention by executing machine readable software code that defines the specific tasks performed by the invention. The microprocessor may also be configured to operate and communicate with other devices, such as direct memory access modules, memory storage devices, internet-related hardware, and other devices involved in the transfer of data in accordance with the present invention. The software code may be configured using software formats such as Java, C + +, XML (extensible markup language), and other languages that may be used to define functions related to the operation of the device required to perform the functional operations associated with the present invention. The code may be written in different formats and styles, many of which are known to those skilled in the art. Different code formats, code configurations, styles, and formats of software programs and other means of configuring code for defining the operation of a microprocessor according to the present invention will not depart from the spirit and scope of the present invention.
Among the different types of devices, such as notebook or desktop computers, handheld devices having a processor or processing logic, and possibly also computer servers or other devices that utilize the present invention, there are different types of storage devices for storing and retrieving information while performing functions in accordance with the present invention. Cache memory devices are often included in such computers for use by the central processing unit as a convenient storage location for frequently stored and retrieved information. Similarly, persistent memory is also frequently used with computers that maintain information that is frequently retrieved by a central processing unit, but unlike cache memory, information does not change frequently in the persistent memory. Main memory is also typically included for storing and retrieving larger amounts of information, such as data and software applications configured to perform functions in accordance with the present invention when executed by a central processing unit. These memory devices may be configured as Random Access Memory (RAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), flash memory, and other memory devices that may store and retrieve information through a central processing unit. During data storage and retrieval operations, these memory devices are switched to have different states, such as different charges, different magnetic polarities, and the like. Thus, systems and methods configured in accordance with the invention described herein enable physical translation of these memory devices. Accordingly, the invention described herein is directed to new and useful systems and methods for enabling a memory device to transition into different states in one or more embodiments. The present invention is not limited to any particular type of memory device or to any common protocol for storing information to and retrieving information from such memory devices, respectively.
The term "machine-readable medium" shall include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term "machine-readable medium" shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine or that cause the machine to perform any one or more of the methodologies of the present invention. A machine-readable medium includes a mechanism that provides (i.e., stores and/or transmits) information in a form readable by a machine (e.g., a computer, PDA, mobile phone, etc.). For example, a machine-readable medium includes a memory (as described above); a magnetic disk storage medium; an optical storage medium; a flash memory device; bioelectrical, mechanical systems; electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). The device or machine readable medium may include micro-electro-mechanical systems (MEMS), nanotechnology devices, organic, holographic, solid-state storage devices, and/or rotating magnetic or optical disks. The device or machine-readable medium may be distributed as portions of the instructions have been separated into different machines, such as across an interconnection of computers or as different virtual machines.
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.
Reference in the specification to "an embodiment," "one embodiment," "some embodiments," or "other embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments. The various appearances of "one embodiment," "an embodiment," or "some embodiments" are not necessarily all referring to the same embodiments. If the specification states a component, feature, structure, or characteristic "may", "might", or "could" be included, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to "a" or "an" element, that does not mean there is only one of the element. If the specification or claims refer to "an additional" element, that does not preclude there being more than one of the additional element.
Unless defined otherwise, all technical, symbolic, and other technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. All patents, applications, published applications, and other applications mentioned herein are incorporated by reference in their entirety. If a definition set forth in this section violates or is inconsistent with a definition set forth in patents, applications, published applications, and other applications incorporated by reference herein, the definition set forth in this section prevails over the definition incorporated by reference herein.
This specification may use relative spatial and/or orientational terms in describing the position and/or orientation of a component, asset, location, feature or part thereof. Unless specifically stated otherwise, such terms as set forth by the context of the specification, including without limitation, top, bottom, above, below, top, above, below, left side, right side, front, rear, immediately adjacent, between, horizontal, vertical, diagonal, longitudinal, transverse, radial, axial, and the like, are used for convenience in referring to such components, equipment, locations, features, or portions thereof in the drawings and are not intended to be limiting.
Moreover, unless otherwise stated, any particular dimensions mentioned in this specification are merely depictions of exemplary implementations of devices embodying aspects of the invention, and are not intended to be limiting.
Methods, systems, and devices include improved security operations and configurations with new approaches to biometric systems. Such a system would greatly benefit from the added security features, particularly in financial transactions. Although the embodiments are described and illustrated in the context of devices, systems, and methods of verifying biometric devices, such as fingerprint sensors, the scope of the present invention extends to other applications in which such functionality is useful. Furthermore, while the foregoing description has been with reference to specific embodiments of the invention, it will be appreciated that these are merely illustrative of the invention and that changes may be made in these embodiments without departing from the principles of the invention, the scope of the changes being defined in the appended claims and their equivalents.